Operating room lights are known in which a plurality of lamps are so arranged that the light beams will overlap in a specific region, so that an increased light intensity is obtained, which, due to the different spatial arrangement of the lamps, does not cast any shadows. Such operating room lights may have handles located thereon, centrally located in the lamp or at the edges thereof, in which the spacing of the lamp with respect to the operating field can be changed. Electric motors can be provided in the operating room lamp to adjust the positions of the lamps so that the light beams emitted therefrom will overlap in accordance with the wishes of the operating doctor.
U.S. Patent No. 4,025,777 describes an operating room lamp which is essentially ring-shaped, for fixed installation in an operating theater. The lower portion of the operating room element, which carries the light emitting surface, is subdivided to provide room for a plurality of light radiating lamps. The light radiators are located so as to be adjustable. Thus, a lamp guiding arrangement, coupled to the lamps, can change the light axes of the operating room lamp without moving the overall unit itself, so that the light beams from the respective lamp units coverage at a point which can be changed horizontally or vertically. The converging point can be previously determined. The individual lamp units are retained in a housing in a gimbal suspension and interconnected by guide rods and springs. The intersecting point of the three spatial axes can thus be shifted by appropriate readjustment of the control system which is formed by the respective guide rods. A carriage is provided which can be shifted along guide rails. The change or shift can be carried out by drive motors.
The overall operating room light is fixedly secured in the theater. This limits the possibility of the emission of light from the operating room fixture, so that, for example, it is not possible to select between horizontal and vertical light emission. Automatic refocussing, if the spacing of the light intersection during an operation should change, is not possible, however.
British Pat. No. 1,537,181 describes an operating room light which has a plurality of light sources to emit light beams therefrom, respectively, in order to provide for uniform illumination of an operating field. The light sources direct their light into two respective deflection mirrors, located in an arm of the light unit. This permits reflection of a light beam from an inner deflection mirror, in part, and further transmission of light, in part, to an external deflection mirror. The inclination of the mirrors with respect to a horizontal axis of the original light beams is adjustable. Thus, each arm of the unit provides two light beams on the field in question. The light beams can be converged. It is necessary to readjust the mirrors if it is required to refocus the position of intersection of the respective light beams in order to compensate for possible changes in spacing between the operating room light and the field to be illuminated.
German Patent Disclosure Document DE-OS 32 27 494 describes an operating room light specifically adapted for dental work and jaw surgery. A light beam remains continuously directed to the oral region of the patient by automatic tracking of a lamp if the patient's chair is moved. The necessary tracking arrangement includes an ultrasonic transmitter located in the region of the head of the patient, and an ultrasound receiver located in the treatment room, as well as a tracking or targeting circuit. Servo motors or stepping motors are provided to ensure tracking, by bringing the lamp holder in predetermined positions, or inclinations, respectively. Such an operating room light cannot be used for general surgery since the ultrasound transmitter must be located in the immediate vicinity of the operating field to be illuminated, that is, in the region of an open wound. For general surgical purposes, such a system cannot be used since an ultrasound transmitter cannot be placed in an open wound. Errors in adjustment as well as difficulties in handling and sterilization impede such application.